Electro-optic mirror cell

Abstract

A reflective element assembly for a variable reflectance vehicular mirror includes a front substrate having a transparent conductive coating disposed on a second surface, and a rear substrate having a third surface conductive coating disposed on its third surface and preferably, a fourth surface conductive coating disposed on its fourth surface. At least a portion of the third surface conductive coating may wrap around an edge portion of the rear substrate and at least a portion of the fourth surface conductive coating may wrap around at least a second portion of the perimeter edge so as to establish electrical continuity between the fourth surface conductive coating on the fourth surface and the third surface conductive coating on the third surface. The rear substrate may have a smaller dimension than the front substrate so as to provide an overhang region, preferably at the wraparound region.

What is claimed is: 
     
       1. A mirror reflective element assembly for a variable reflectance vehicular mirror, said mirror reficetive element assembly comprising:
 a front substrate having a first surface and a second surface, said second surface having a transparent electrically conductive coating disposed thereon; 
 a rear substrate having a third surface and a fourth surface, said rear substrate comprising a perimeter edge around its perimeter and between said third surface and said fourth surface; 
 said third surface having an electrically conductive coating disposed thereon, at least a portion of said third surface conductive coating continuing from said third surface over at least a first portion of said perimeter edge, said third surface conductive coating establishing electrical continuity between said third surface and said first portion of said perimeter edge; 
 said fourth surface having a fourth surface electrically conductive coating disposed thereon, at least a portion of said fourth surface conductive coating continuing from said fourth surface over at least a second portion of said perimeter edge, said fourth surface conductive coating establishing electrical continuity between said fourth surface and said second portion of said perimeter edge; 
 said first portion of said perimeter edge and said second portion of said perimeter edge at least partially coinciding at a perimeter edge overlap region whereby electrical continuity is established between said fourth surface conductive coating on said fourth surface said rear substrate and said third surface conductive coating on said third surface of said rear substrate; 
 an electro-optic medium disposed between said second surface conductive coating and said third surface conductive coating; and 
 a first electrical connection at said fourth surface making electrical contact with said fourth surface conductive coating, said first electrical connection being operable to power said third surface conductive coating via electrical conduction between said fourth surface conductive coating and said third surface conductive coating at said overlap region. 
 
     
     
       2. The mirror reflective element assembly of  claim 1 , wherein said fourth surface conductive coating comprises at least one electrically conductive coating selected from the group comprising a vacuum deposited electrically conductive coating, an electrically conductive polymeric coating, an electrically conductive solder coating, and an electrically conductive frit coating. 
     
     
       3. The mirror reflective element assembly of  claim 1 , wherein said fourth surface conductive coating comprises a conductive epoxy coating. 
     
     
       4. The minor reflective element assembly of  claim 1 , wherein said fourth surface conductive coating comprises a sputtered metallic coating. 
     
     
       5. The mirror reflective element assembly of  claim 1 , wherein said overlap region extends for a distance of at least about 5 mm along said perimeter edge of said rear substrate. 
     
     
       6. The mirror reflective element assembly of  claim 1 , wherein said fourth surface includes a heater element disposed thereon, said heater element, when powered, heating said fourth surface of said reflective element assembly. 
     
     
       7. The mirror reflective element assembly of  claim 6 , wherein said heater element comprises another electrically conductive coating disposed on said fourth surface, said another electrically conductive coating electrically isolated from said fourth surface conductive coating. 
     
     
       8. The mirror reflective element assembly of  claim 7 , wherein said another electrically conductive coating and said fourth surface conductive coating comprise similar materials. 
     
     
       9. The mirror reflective element assembly of  claim 1 , wherein said third surface conductive coating and said fourth surface conductive coating comprise similar materials. 
     
     
       10. The mirror reflective element assembly of  claim 9 , wherein said third and fourth surface conductive coatings are established in a unitary operation. 
     
     
       11. The mirror reflective element assembly of  claim 1 , wherein formation of said reflective element assembly includes mating a rear substrate cut to the shape of the vehicular mirror to a front substrate portion of a transparent electrically conductive coated sheet of substrate material that is dimensioned to be larger than at least two side-by-side rear substrates that are cut to the shape of the vehicular mirror, and wherein at least two separate mirror elements are formed by separation from said sheet of substrate material of at least two rear substrate shapes mated to at least two respective front substrate portions. 
     
     
       12. The mirror reflective element assembly  claim 11 , wherein said at least two respective front substrate portions each include a perimeter band in a shape that corresponds to the shape of the vehicular mirror. 
     
     
       13. The mirror reflective element assembly of  claim 1 , wherein said second surface of said front substrate includes a perimeter band disposed around a perimeter border of said second surface. 
     
     
       14. The mirror reflective element assembly of  claim 13 , wherein said perimeter band comprises a metallic reflective material. 
     
     
       15. The mirror reflective element assembly of  claim 13 , wherein said perimeter band comprises a non-reflective material. 
     
     
       16. The mirror reflective element assembly of  claim 1 , wherein said rear substrate has a smaller dimension than said front substrate. 
     
     
       17. The mirror reflective element assembly of  claim 16 , wherein said overlap region is along a portion of said perimeter edge of said rear substrate that is recessed from a corresponding portion of a perimeter edge of said front substrate. 
     
     
       18. The mirror reflective element assembly of ciaim  1 , wherein the vehicular mirror comprises an interior vehicular mirror. 
     
     
       19. The mirror reflective element assembly of  claim 1 , wherein the vehicular mirror comprises an exterior vehicular mirror.